JP2964593B2 - Color image recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image recording apparatus such as a color copy and a color printer, and more particularly, to a sufficient color reproduction regardless of a color distribution of a color original. The present invention relates to a color image recording apparatus capable of performing the following.

2. Description of the Related Art Conventionally, a color image recording apparatus of this type can input a color information signal of a color original and record the color information signal and its color stored in a storage means in an achromatic color direction by a recording means. Based on a plurality of combination data with a control signal for recording a color that has been compression-converted to a specific color by a constant rule with a control signal, by performing processing such as interpolation processing, the recording means corresponding to the color information signal A control signal is generated, and color recording is performed using cyan, magenta, and yellow inks or toners according to the obtained control signal.

[Problems to be Solved by the Invention] Generally, in a color original, the ratio of colors that can be recorded by a recording unit and the degree of colors that cannot be recorded are different for each original. As a result, with a certain color compression means, the contrast of the recorded image may be insufficient due to excessive color compression in some color originals, or conversely, saturated colors may still exist due to insufficient color compression. It was difficult to reproduce.

The present invention has been made to solve the above-described problem, and has as its object to provide a color image recording apparatus that always has good color reproducibility regardless of the color distribution of a color original.

[Means for Solving the Problems] To achieve this object, the present invention provides, as shown in FIG. 1, an input means 51 for inputting a color information signal corresponding to the color of a color original, and at least cyan ink. Recording means 52 for performing color recording using three color materials of magenta and yellow
Storage means 53 for storing combination data of a recording color of the recording means 52 and a control signal for activating the means.
And the data stored in the storage unit 53 so that the recording color when the recording unit 52 is operated based on the color information signal from the input unit 51 is substantially the same as the color of the color original. A color image recording apparatus having a color correction means for determining a control signal of the recording means based on the pre-scanning means for pre-scanning the color original and obtaining color distribution information of the original; The means 53 stores a plurality of types of combination data of recording colors and control signals corresponding to the color distribution information of the color original, and the color correction means
Reference numeral 54 includes a selection unit 56 for selecting desired data from the combination data stored in the storage unit 53 in accordance with the distribution information obtained by the pre-scanning unit 55.

Further, the storage unit 53 stores the color information signal and a color information signal recordable by the recording unit 52 in the achromatic color direction with respect to the color information signal in a method or a ratio according to the color distribution information of the color original. It is possible to use a combination of a plurality of data stored together with a control signal for recording the compression-converted color by the recording means 52.

[Operation] In the above configuration, first, the color original is scanned by the pre-scanning means 55.
To roughly input color distribution information of a color original. Thereafter, the color information signal of the color original is input in pixel units by the input means 51, and a plurality of combinations of the control signal of the recording means 52 and the color information signals stored in the storage means 53 are selected by the selection means 56 according to the color distribution information. A control signal of the recording means 52 is selected based on the combination of the colors, and the color information signal input thereto is interpolated using interpolation processing or the like from the combination, and cyan, magenta, and yellow are recorded by the recording means 52 according to the generated control signal. Color recording is performed using ink or toner.

[Example] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 2 and FIG.
The configuration of the entire color copying machine will be described. The digital color copying machine (main body) 1 of this embodiment includes a color document reading section 2, a color image processing section 3, and a color image recording section 4.

The color document reading unit 2 is configured on an upper part of the main body 1. Above the color document reading section 2, there is provided a transparent document table 5 on which a color document is placed, and a document cover 6 which can cover the transparent document table 5 and press the color document. A fluorescent light 7 for a scanner light source is provided below the transparent platen 5 so as to extend in the front-rear direction (main scanning direction) in FIG.
Is configured to generate light toward the transparent document table 5. The movable reflecting mirror 8 is provided on a movable table 10 for moving the fluorescent light for scanner light source 7, and is configured to reflect the light emitted from the fluorescent light for scanner light source 7 and reflected by the color original. The lens 11 concentrates the light reflected by the movable reflecting mirror 8, and the filter 12 decomposes the light concentrated by the lens 11 into red, green, and blue components, and a solid-state image sensor (CCD) 1
3 takes in the light decomposed by the filter 12 and converts it into an electric signal.

All of the lens 11, the filter 12, and the solid-state imaging device 13 are installed on the movable base 10. Light source moving device 9
Are fluorescent light for scanner light source 7, movable reflecting mirror 8, lens 1
1, the filter 12, and the solid-state imaging device 13 are moved together with the moving table 10 in the left-right direction (sub-scanning direction) in FIG. A document feeder 16 is provided at an end of the color document reading unit 2, and sends a color document on the document feeder 14 to the transparent document table 5 via the color document feeder 15. On the opposite side of the document feed table 14, a document discharge tray 17 for discharging a color document after copying is provided.

The color image recording section 4 is configured below the main body 1. The color image recording unit 4 includes a laser 23, a laser control unit 24 for outputting a signal for driving the laser 23, and a polygon mirror.
A laser modulation unit 26 that emits laser light from a laser 23 is provided at 25. The photoconductor drum 27 is provided so as to be exposed by the laser beam reflected by the polygon mirror 25. The charger 28 is provided around the photosensitive drum 27 so as to uniformly charge the photosensitive drum 27 negatively. Photoconductor drum 27 charged by charger 28
Is irradiated with a laser beam to form an electrostatic latent image.
Cyan developing device 29, magenta developing device 30, yellow developing device 31
Are configured to adhere cyan, magenta, and yellow toners to the electrostatic latent image on the photosensitive drum 27. Cyan toner supply 32, magenta toner supply
33, a yellow toner supply unit 34 is for supplying toner to each developing unit. Around the photosensitive drum 27, a cleaner 35 for removing residual toner on the photosensitive drum 27 is provided.

Further, beside the photosensitive drum 27, a transfer drum 37 for transferring the toner image on the photosensitive drum 27 to the recording paper supplied from the paper supply case 36, and a fixing unit for thermally fixing the transferred recording paper. 38 are installed. On the downstream side of the fixing unit 38 in the sheet conveyance direction, a paper feeding unit 40 for discharging the fixed paper to the output tray 39 is provided.

As shown in FIG. 3, the color image processing unit 3 converts a color original information signal corresponding to a color information signal obtained from the solid-state image sensor 13 from an analog electric signal to a digital electric signal. A / D converter) 18
A document storage device (image memory) 19 for storing a part of color document information by digital electric signals, and a plurality of compression ratios having different methods or ratios determined in advance according to color distribution information of color documents described later. ROM 20 storing a combination of a printer control signal and a recording color, a RAM 21 storing each calculation result, and a CPU 22 performing various image processing using the same.
And a laser control unit 24 that drives a laser 23 of the color image recording unit 4 based on a signal after a color correction process described later.

Next, the operation of the digital color copying machine 1 having the above configuration will be described with reference to FIGS.

The color document on the document feeder 14 is sent to the transparent platen 5 by the document feeder 16. The document cover 6 may be opened directly and placed on the transparent document table 5. In this state, first, in step S1, pre-scanning (pre-scanning) is performed to obtain distribution information on the color of the color original.
In the pre-scanning, when the light source moving device 9 moves the fluorescent light 7 for the scanner light source in the sub-scanning direction, the color distribution information of the original is read while skipping pixels in the same direction at regular intervals, that is, sampling. . At this time, the white light emitted by the scanner light source fluorescent lamp 7 is reflected by the movable reflecting mirror 8, passes through the lens 11 and the filter 12, and is converted into an electric signal by the solid-state imaging device 13. The filter 12 is divided so as to transmit only the red, green, and blue components, and is divided by moving the light source moving device 9.
Is moved, and the filter 12 is turned on every one line in the main scanning direction.
It changes according to red, green, and blue.

An analog electric signal obtained from the solid-state imaging device 13 is converted into a digital color signal by an analog-to-digital converter 18 with respect to discrete pixels (pixels of interest), and the original storage device
Stored in 19.

Next, the distribution of the color document in the color space is examined based on the contents obtained by the pre-scanning. That is, step S2
Converts the digital signal of the pixel of interest into a CIE-L ^* a ^* b ^* color system value. In this case, if the input signal satisfies the router condition in the input system, the input RGB signal is
Can be converted to -XYZ values. Then, the value of CIE-XYZ (X, Y,
Z) to CIE-L ^* a ^* b ^* color system values (L ^* , a ^* , b ^* )
Can be converted by the following equation.

L ^* = 116 × (Y / Yn) ^1/3 −16 (1) a ^* = 500 × ｛(Χ / Χn) ^1/3 − (Y / Yn) ^1/3 ｝... (2) b ^* = 200 × {(Y / Yn) ^1/3 − (Z / Zn) ^1/3 } (3) where Δn, Yn, and Zn are CIE-XYZ tristimulus values of the perfect diffusion surface.

Then, in step S3, the target achromatic color L of the target pixel is
^The distance M1 is obtained from ^{* '} (one point on the L ^* axis generally using a value of 50 to 60) as in the following equation.

M1 = ｛(L ^* −L ^{* ′} ) ² + a ^* ₂ + b ^* ₂ ｝ ^1/2 (4) Next, in step S4, the hue from the target achromatic color of the target pixel and the lightness direction are used for the recording system. The distance M2 of the color reproduction range from the target achromatic color is obtained from the table table1 obtained in advance and stored in the ROM 20 as shown in the following formula.

θ = tan ⁻¹ ｛(L ^* −L ^{* ′} ) ² / (a ^* ₂ + b ^* ₂ ) _1/2 ｝ (5) φ = tan ⁻¹ (b ^* / a ^* )… (6) M2 = table1 [θ] [φ] (7) Then, the value of the ratio between M1 and M2 is stored in the RAM 21 in step S5. When the pre-scan for all the areas is completed by repeating the above operation (YES in step S6), the non-compression ratio R is calculated as follows in step S7 according to the value of the ratio of all the pixels obtained in the pre-scan. Ask for.

Here, 1.0>R> 0, and n is the number of pre-scanned pixels.

In accordance with the non-compression rate R, a combination of a plurality of printer control signals and input colors created in advance in the ROM 20 using the non-compression rate R is selected. The combination stored in the ROM 20 is a printer control signal corresponding to an input color on a grid for each of three components of a recording color described later.

Next, in step S8, main scanning is performed. In the main scanning, the scanner light source fluorescent lamp 7 and the like are moved in the sub-scanning direction by the light source moving device 9 (in this case, there is no gap), and the white light emitted from the scanner light source fluorescent lamp 7 is reflected by the movable reflecting mirror 8. Then, the light passes through a lens 11 and a filter 12 and is converted into an electric signal by the solid-state imaging device 13.

An analog electric signal obtained from the solid-state imaging device 13 is converted into a digital color signal by an analog / digital converter 18 for each pixel (pixel of interest) and stored in a document storage device 19. In step S9, it is checked in which grid the color indicated by the signal corresponds to the stored digital signal of the target pixel.

Then, in step S10, a printer control signal corresponding to each vertex color of the grid is fetched from the ROM 20, and is used to interpolate (interpolate) in step S11 according to the following interpolation formula.

Here, Lij (i = C, M, Y) is a printer control signal of a color corresponding to each stored vertex of the grid, and Mj is a color indicated by the digital signal of the pixel of interest including the vertex of the diagonal grid. And Di is the printer control signal of the interpolated target pixel.

The printer control signal for each component obtained by the above-described color correction processing is sent to the laser control unit 24, laser light is emitted according to this data, and the laser light is reflected by the polygon mirror 25, and is uniformly emitted by the charger 28. Charged photoconductor drum 27
To form a latent image on the photosensitive drum 27. According to the latent image, the toner is developed by one of the cyan developing unit 29, the magenta developing unit 30, and the yellow developing unit 31 according to the separated color of the corresponding data. Then, the recording paper supplied from the paper supply case 36 is transferred to the transfer drum.
The toner image is wound around the photosensitive drum 27 and is transferred to a recording sheet. Further, the residual toner on the photosensitive drum 27 is removed by the cleaner 35. The transferred recording paper is heat-fixed by the fixing unit 38 in the middle of the paper feeding unit 40, and is output to the output tray.
Discharged to 39.

Next, a method of creating combination data of the input colors and the printer control signals stored in the ROM 20 will be described.

First, in step S21, in step S21, the target color is divided into the above-described formulas (1) to (3). ) To CIE-L ^* a ^* b ^* color system values. In steps S22 and S23, the CIE-L ^*
From the values of the a ^* b ^* color system, the distance M1 to the achromatic color of the target lightness of the target color (hereinafter referred to as the target achromatic color) and the target color of the target color as shown in the above equations (4) to (7). The distance M2 from the target achromatic color in the color reproduction range of the recording system is determined in the hue and lightness directions from the color.

Next, in step S24, in the hue and lightness direction of the target color from the target achromatic color, the document type in the document selection button (not shown), for example, the distance M3 from the target achromatic color in the color reproduction range of the photo document, Reference is made from the previously obtained table table2 as in the above equations (5) to (7).

It is checked in step S25 whether or not the distance M1 of the target color from the target achromatic color falls within the uncompressed ratio R times the distance M2 in the color reproduction range of the recording system. If it is not included, the color compression conversion is not performed. If it is included, the distance from the target achromatic color of the target color after color compression in step S26 as shown in the following equation
Find M4.

M4 = M2− (1.0−R) × M2 / {M3−R × M2} × {M2−M1} (10) Then, in step S27, the CIE-L of the target color is calculated as in the following equation.
^{* A *} b ^* Changes the value of the color system.

L ^* ₂ = (L ^* −L ^{* ′} ) × M4 / M1 + L ^{* ′} (11) a ^* ₂ = a ^* × M4 / M1 (12) b ^* ₂ = b ^* × M4 / M1 (13) After that, in step S28, the original scanner input is again converted into the RGB value of the color system. Further, in step S29, the RGB
The printer control signal for recording the value is set as the printer control signal of the target color.

The above operation is performed for all the grid-like colors and the uncompressed ratio R =
The data creation is completed by performing the operations on 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 and storing the results in the ROM 20.

The present invention is not limited to the above embodiment, and various changes can be made without departing from the scope of the present invention. For example, the combination data of the color-compressed recording colors and control signals to be stored in the ROM 20 is as described above. It is not limited to what you want. Further, in this embodiment, the digital
Although a color copier is used, the present invention can be applied to a color printer without a color document reading unit. Further, in this embodiment, color recording is performed in three colors of cyan, magenta, and yellow, but recording may be performed in four colors in which black is added thereto.

[Effects of the Invention] As described above, according to the present invention, a color document is pre-scanned, the color distribution of the document is checked, and data created by performing color compression with a color compression ratio suitable for the color distribution of the document. , A control signal for recording is appropriately selected, so that color correction can always be appropriately performed regardless of the color distribution of a color original, and a color image with good color reproducibility can be recorded. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of the apparatus of the present invention, and FIG.
FIG. 3 is a block diagram of the entire apparatus according to the present embodiment, FIG. 3 is a block diagram of a color image processing unit of the apparatus, and FIGS.
Is a flowchart showing the operation of the present apparatus, and FIG. 5 is a flowchart showing a procedure for storing data in the storage means. DESCRIPTION OF SYMBOLS 1 ... Digital color copier, 2 ... Color original reading section, 3 ... Color image processing section, 4 ... Color image recording section, 20 ... RAM, 21 ... ROM, 22 ... CPU, 51 ... ... input means, 52 ... recording means, 53 ... storage means, 54 ... color correction means, 55 ... pre-scanning means, 56 ... selection means.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 1/40-1/409 H04N 1/46 H04N 1/60

Claims (2)

(57) [Claims] An input unit for inputting a color information signal corresponding to a color of a color original; a recording unit for performing color recording using at least three color materials of cyan, magenta, and yellow; A storage unit for storing combination data of a recording color and a control signal for activating the unit; and a recording color when the recording unit is activated based on a color information signal from the input unit. A color correction unit for determining a control signal of the recording unit based on the data stored in the storage unit so that the color document has substantially the same color as the color document. Pre-scanning means for obtaining color distribution information of the color document, wherein the storage means stores a plurality of types of combination data of recording colors and control signals corresponding to the color distribution information of the color original, Wherein the color correcting means has a selecting means for selecting desired data from the combination data stored in the storing means in accordance with the distribution information obtained by the pre-scanning means. apparatus. 2. A color information signal and a color recordable by the recording means in an achromatic color direction with respect to the color information signal in a method or a ratio according to color distribution information of a color original. 2. A color image recording apparatus according to claim 1, wherein a plurality of data combined with a control signal for recording a color that has been compression-converted into an information signal by said recording means is stored.